The 21st century may be referred to as the nano-era, while the 20th century is represented by microtechnology. Nanotechnology may generally be categorized as comprising nanomaterials, nanodevices, as well as environmental and biotechnological technologies, according to applications thereof.
Nanotechnology is the artificial manipulation of ultrafine matter on the atomic or molecular scale to form or fabricate materials or devices having new properties and functions. At present, nanotechnology is regarded as a key cutting-edge technology for in the areas of both information technology (IT) and biotechnology (BT).
Nanotechnology provides a range of advantages and merits throughout industrial fields, such that some may speak of another technological revolution occurring. However, it is regarded that nanotechnology has potential dangers that may originate from the characteristics of nanotechnology.
Since smaller particles have greater specific surface areas, fine particles having such increased specific surface areas are increased in toxicity when reacting with biotissues. For example, as demonstrated in previous academic experiments, the toxicity of specific nanoparticles, such as titanium dioxide, carbon powder, and diesel particles, for example, increases with decreases in the sizes thereof, thereby causing inflammation. In addition, ultrafine nanoparticles may be deeply lodged in lung cells or move to the brain without being filtered by the respiratory tract or mucosa. Moreover, according to a plurality of recent studies, it has been theorized that there may be links between nanoparticles accumulated in the human body and diseases or disorders of the central nervous system.
Recently, with the development of nanotechnology, stability evaluation of nanotechnology has also been actively conducted. As a representative method of evaluating toxicity generated when nanoparticles are inhaled and accumulated in the human body, inhalation toxicity testing of nanoparticles has been undertaken with various laboratory animals. Data relating to nanoparticle harmfulness to the human body acquired through inhalation toxicity testing of nanoparticles is used as base data relating to nanoparticles in the manufacturing of products such as nanofibers, cosmetics, semiconductors, and drug carriers across a range of industrial fields.
Recently, as the importance of nanotechnology has come to prominence, not only inhalation toxicity testing of nanoparticles, but also various other experiments, such as effectiveness testing on nanoparticles with respect to the human body, stability testing on nanoparticles, and environmental effect evaluation of nanoparticles, have been conducted. A variety of experiments are conducted substantially in the same manner as inhalation toxicity testing, since all of such experiments evaluate effects of nanoparticles on the human body. Thus, hereinafter, a variety of experiments on nanoparticles will collectively be referred to as inhalation toxicity testing.
In addition, nanoparticles are aerosol particles, and testing of nanoparticles may be equally applied to testing of aerosol particles having submicron diameters. Thus, hereinafter, the term “nanoparticles” used herein will be interpreted as including the concept of submicron particles, unless otherwise specified.
Inhalation toxicity testing of nanoparticles as described above is typically conducted by supplying an aerosol of nanoparticles into an exposure chamber having a predetermined size, exposing a laboratory animal inserted into the exposure chamber to the nanoparticles, and then measuring a variety of changes in the laboratory animal. More specifically, a hollow pipe having the shape of a vertical tower is disposed within a single chamber housing, a plurality of laboratory animal restraining units, into each of which a laboratory animal is inserted, are fitted to the hollow pipe to communicate with the hollow pipe, and a separate particle supply unit is connected to the vertical tower-shaped hollow pipe, such that nanoparticles produced by the particle supply unit are supplied to the laboratory animals confined in the laboratory animal restraining units.
Nanoparticles must be supplied in different concentration levels to the laboratory animal restraining units to obtain more diverse and accurate testing results on the effects of nanoparticles. In this regard, a method of preparing a plurality of chamber housings as described above and supplying nanoparticles having different concentration levels to the hollow pipes and the laboratory animal restraining units disposed within the chamber housings is generally used.
According to this method, a large scale and expensive operating costs are required for an inhalation toxicity testing device for nanoparticles, since a plurality of chamber housings for supplying nanoparticles in different concentration levels, as well as air circulating equipment, must be provided. Thus, such inhalation toxicity testing of nanoparticles having different concentration levels has been conducted in professional research institutes and testing agencies but cannot be conducted in small laboratories, such as university laboratories. In particular, even in the case in which inhalation toxicity testing is to be conducted in a small scale and in a relatively simple manner, a plurality of chamber housings must be provided in a considerable scale, thereby leading to degraded space efficiency and increased testing costs, which are problematic. It is also difficult to conduct testing in more various manners as required by the user.